Characterization of Unsteady Interaction Phenomena of Shock Waves and Turbulent Boundary Layers in Supersonic Internal Flows

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In order to obtain principles for optimum designs of scramjet engines, this study aims to clarify the structure and the characteristics of shock wave/boundary layer interactions in a rectangular duct imitating a separator between the intake and the combustor in scramjet engines.Firstly, the following techniques were established for a particle imaging velocimetry with high resolution and stability :1.An Impinging-type nozzle, which can inject water particles directly into the settling chamber of supersonic wind tunnels, was designed and applied to seeding of tracer particles. Water particles with sufficiently small diameter of μm were produced due to air-assisted atomizing effects and followed the air flows satisfactorily.2.Traverse equipments with high rigidity and optical equipments with high resolution were assembled. Errors in flow speed measurements were reduced to be 2.6%.In addition, the structure of turbulent boundary-layer separation on walls was investigated as follows :3.A technique for visualizing shearing stress distributions on walls using cholestric liquid crystal was established.4.High-speed changes in pressure distributions on walls were measured and analyzed using high-speed pressure transducers.5.Detailed structure of the flow field was analyzed by computational fluid dynamics.Consequently, the principle structure and the mechanism of shock wave/boundary layer interactions in a rectangular duct were clarified.